To impart excellent appearance, properties, etc. to the surface of a substrate, a coating film is conventionally formed on the surface of the substrate by applying a coating composition to the surface of the substrate to form a wet coating film and curing the wet coating film. As the coating composition, active energy ray-curable coating compositions, in which the curing of a wet coating film is carried out with active energy rays, have been studied from the viewpoint of, for example, saving energy and improving productivity.
Further, in recent years, application of such an active energy ray-curable coating composition to substrates with a relatively large area to be coated, such as home electric appliances and interior and exterior automobile parts, has been considered. However, in forming a coating film on a substrate with a relatively large area to be coated, foreign matter, including dirt and dust, may adhere to the wet coating film surface and be stuck on the cured coating film, resulting in defects in the coating film.
Such defects in the coating film are commonly repaired by removing the foreign matter causing the defects, by sanding the cured coating film, and subsequently erasing the traces left by sanding, with polishing powder. Thus, there is recently demand for an active energy ray-curable coating composition capable of forming a coating film with excellent appearance and such excellent repairability that the foreign matter on the coating film can be removed while maintaining the excellent appearance.
Patent Literature 1 discloses that a coating composition containing a (meth)acryloyl group-containing polypentaerythritol, a urethane poly(meth)acrylate compound having radical-polymerizable unsaturated double bonds, a (meth)acryloyl group-containing (iso)cyanurate, an ultraviolet absorber, and a photopolymerization initiator in specific amounts is capable of forming, on the surface of a substrate, a crosslinked cured film with excellent abrasion resistance, surface smoothness, thermal resistance, chemical resistance, durability, weather resistance, and adhesion to the substrate by active-energy-ray irradiation. However, a coating film formed from the coating composition is problematic in that the repairability is insufficient.